It's also caused by absurd nonsense like how doctors can't tell you how much anything they're proposing to do actually will cost (a necessary condition for entering into a contract!), but then the system makes up arbitrary bills after the fact - with fraudulent amounts that nobody actually pays! No other industry works like that, as it's not the foundation of a market in the first place. Imagine if going to the grocery store involved "paying" some token amount at the cashier for their time to put your items in bags, then for the food you received shakedown bills for years afterwards, that you had to spend time going through your old documentation to refute and bargain down. Absurd.

Regardless of "insurance", who is ultimately paying, or subsidies to provide a baseline of care - there needs to be reform that mandates simple up-front prices, constant per-provider regardless who is paying, and ruling out any other theory of billing. Doctors throw up their hands and act like they're dealing with some special problems, but there are plenty of other industries we can look at for the dynamics of how to handle routine procedures versus emergencies (and knowns vs unknowns) in a consensual and market-responsive manner.